(1) Field of the Invention
This invention pertains to apparatus for limiting leakage from ferro-hydrodynamic bearings of the type described, for example, in United States class 308/10.
(2) Description of the Prior Art
United Kingdom Pat. No. 783,881 teaches the use of liquids containing ferromagnetic particles as gas seals. The liquids are concentrated in a desired region adjacent a rotatable shaft by electromagnets having contoured poles.
U.S. Pat. No. 3,483,969 pertains to a method for separating materials of different density wherein a controlled magnetic field is passed through a ferro-fluid. A magnetic sieve approach is used wherein the field intensity and magnetic field gradient is varied in a predetermined distribution to create a non-uniform distribution of levitation forces.
U.S. Pat. No. 3,612,630 pertains to a bearing using a fluid pad between two surfaces having relative motion with respect to each other. The pad contains magnets which define a magnetic gap having a predetermined configuration on a predetermined periphery. The gap contains magnetic flux which captures magnetic fluid. The fluid produces a seal.
U.S. Pat. No. 3,620,584 pertains to a means for axially sealing a shaft using knife edge magnets for concentrating magnetic flux around the shaft to hold ferrofluid seals in place.
U.S. Pat. No. 3,780,593 pertains to a fluid bearing suitable for use in a gyroscope. The bearing has conical bearing surfaces with a substantially uniform gap therebetween. The gap is filled with ferro-magnetic fluid to support one of the bearing surfaces and keep the bearing surfaces separated. At the end of the conical bearing surfaces, is a conically divergent reservoir for storing the overflow of fluid, such overflow being caused by temperature variations, and the like.
U.S. Pat. No. 3,726,574 pertains to a Ferrohydrodynamic low friction bearing. An overlapping flange is used to minimize leakage.
U.S. Pat. No. 3,746,407 pertains to another ferrohydrodynamic bearing wherein the opposing bearing faces are substantially parallel with a ferro fluid between the bearing faces.
U.S. Pat. No. 3,891,282 teaches an apparatus having knife edge seals against a shaft. The sealing blades are magnetized to contain a ferro-fluid.
U.S. Pat. No. 3,918,773 pertains to a thrust bearing using ferro-fluids and a knife edge to concentrate the magnetic field to hold the fluid at the knife edge, thereby producing a fluid seal.